converter.py 文件源码

def __call__(self):
        # if no data have been set, this will tank with a ValueError
        try:
            dmin, dmax = self.viewlim_to_dt()
        except ValueError:
            return []

        if dmin > dmax:
            dmax, dmin = dmin, dmax
        # We need to cap at the endpoints of valid datetime

        # TODO(wesm) unused?
        # delta = relativedelta(dmax, dmin)
        # try:
        #     start = dmin - delta
        # except ValueError:
        #     start = _from_ordinal(1.0)

        # try:
        #     stop = dmax + delta
        # except ValueError:
        #     # The magic number!
        #     stop = _from_ordinal(3652059.9999999)

        nmax, nmin = dates.date2num((dmax, dmin))

        num = (nmax - nmin) * 86400 * 1000
        max_millis_ticks = 6
        for interval in [1, 10, 50, 100, 200, 500]:
            if num <= interval * (max_millis_ticks - 1):
                self._interval = interval
                break
            else:
                # We went through the whole loop without breaking, default to 1
                self._interval = 1000.

        estimate = (nmax - nmin) / (self._get_unit() * self._get_interval())

        if estimate > self.MAXTICKS * 2:
            raise RuntimeError(('MillisecondLocator estimated to generate %d '
                                'ticks from %s to %s: exceeds Locator.MAXTICKS'
                                '* 2 (%d) ') %
                               (estimate, dmin, dmax, self.MAXTICKS * 2))

        freq = '%dL' % self._get_interval()
        tz = self.tz.tzname(None)
        st = _from_ordinal(dates.date2num(dmin))  # strip tz
        ed = _from_ordinal(dates.date2num(dmax))
        all_dates = date_range(start=st, end=ed, freq=freq, tz=tz).asobject

        try:
            if len(all_dates) > 0:
                locs = self.raise_if_exceeds(dates.date2num(all_dates))
                return locs
        except Exception:  # pragma: no cover
            pass

        lims = dates.date2num([dmin, dmax])
        return lims